diff options
Diffstat (limited to 'arch/arm/mach-u300/timer.c')
| -rw-r--r-- | arch/arm/mach-u300/timer.c | 53 |
1 files changed, 41 insertions, 12 deletions
diff --git a/arch/arm/mach-u300/timer.c b/arch/arm/mach-u300/timer.c index cce53204880e..3ec58bd2d6e4 100644 --- a/arch/arm/mach-u300/timer.c +++ b/arch/arm/mach-u300/timer.c @@ -9,21 +9,26 @@ * Author: Linus Walleij <linus.walleij@stericsson.com> */ #include <linux/interrupt.h> +#include <linux/sched.h> #include <linux/time.h> #include <linux/timex.h> #include <linux/clockchips.h> #include <linux/clocksource.h> #include <linux/types.h> #include <linux/io.h> +#include <linux/clk.h> +#include <linux/err.h> #include <mach/hardware.h> /* Generic stuff */ +#include <asm/sched_clock.h> #include <asm/mach/map.h> #include <asm/mach/time.h> #include <asm/mach/irq.h> -#include "clock.h" +/* Be able to sleep for atleast 4 seconds (usually more) */ +#define APPTIMER_MIN_RANGE 4 /* * APP side special timer registers @@ -307,8 +312,6 @@ static struct clock_event_device clockevent_u300_1mhz = { .name = "GPT1", .rating = 300, /* Reasonably fast and accurate clock event */ .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT, - /* 22 calculated using the algorithm in arch/mips/kernel/time.c */ - .shift = 22, .set_next_event = u300_set_next_event, .set_mode = u300_set_mode, }; @@ -341,18 +344,47 @@ static struct clocksource clocksource_u300_1mhz = { .rating = 300, /* Reasonably fast and accurate clock source */ .read = u300_get_cycles, .mask = CLOCKSOURCE_MASK(32), /* 32 bits */ - /* 22 calculated using the algorithm in arch/mips/kernel/time.c */ - .shift = 22, .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; +/* + * Override the global weak sched_clock symbol with this + * local implementation which uses the clocksource to get some + * better resolution when scheduling the kernel. We accept that + * this wraps around for now, since it is just a relative time + * stamp. (Inspired by OMAP implementation.) + */ +static DEFINE_CLOCK_DATA(cd); + +unsigned long long notrace sched_clock(void) +{ + u32 cyc = readl(U300_TIMER_APP_VBASE + U300_TIMER_APP_GPT2CC); + return cyc_to_sched_clock(&cd, cyc, (u32)~0); +} + +static void notrace u300_update_sched_clock(void) +{ + u32 cyc = readl(U300_TIMER_APP_VBASE + U300_TIMER_APP_GPT2CC); + update_sched_clock(&cd, cyc, (u32)~0); +} + /* * This sets up the system timers, clock source and clock event. */ static void __init u300_timer_init(void) { - u300_enable_timer_clock(); + struct clk *clk; + unsigned long rate; + + /* Clock the interrupt controller */ + clk = clk_get_sys("apptimer", NULL); + BUG_ON(IS_ERR(clk)); + clk_enable(clk); + rate = clk_get_rate(clk); + + init_sched_clock(&cd, u300_update_sched_clock, 32, rate); + /* * Disable the "OS" and "DD" timers - these are designed for Symbian! * Example usage in cnh1601578 cpu subsystem pd_timer_app.c @@ -390,15 +422,12 @@ static void __init u300_timer_init(void) writel(U300_TIMER_APP_EGPT2_TIMER_ENABLE, U300_TIMER_APP_VBASE + U300_TIMER_APP_EGPT2); - /* This is a pure microsecond clock source */ - clocksource_u300_1mhz.mult = - clocksource_khz2mult(1000, clocksource_u300_1mhz.shift); - if (clocksource_register(&clocksource_u300_1mhz)) + if (clocksource_register_hz(&clocksource_u300_1mhz, rate)) printk(KERN_ERR "timer: failed to initialize clock " "source %s\n", clocksource_u300_1mhz.name); - clockevent_u300_1mhz.mult = - div_sc(1000000, NSEC_PER_SEC, clockevent_u300_1mhz.shift); + clockevents_calc_mult_shift(&clockevent_u300_1mhz, + rate, APPTIMER_MIN_RANGE); /* 32bit counter, so 32bits delta is max */ clockevent_u300_1mhz.max_delta_ns = clockevent_delta2ns(0xffffffff, &clockevent_u300_1mhz); |